Therapeutic effect of thymoquinone against lead-induced testicular histological damage in male Wistar rats.

Lead (Pb) is a nonthreshold multi-targeted toxicant that causes alterations in different organs of the body, especially the gonads. This study was aimed to investigate the possible protective effect of thymoquinone (TQ), the major active ingredient of volatile oil of Nigella sativa seeds, against Pb-induced testicular histological damage. Adult male rats were randomised into four groups as follows: control group received no treatment, Pb group was exposed to 2000 ppm of Pb acetate in drinking water, Pb-TQ group was cotreated with Pb plus TQ (5 mg/kg/day, per os) and TQ group receiving only TQ. All treatments were applied for five weeks. Results showed that Pb exposure produced morphological changes in the testis, especially degeneration of germinal epithelium, sloughing of germ cells into the lumen of seminiferous tubules and reduction in the number of luminal spermatozoa. Interestingly, coadministration of TQ to the metal-treated animals prevented the testicular adverse effects. In conclusion, our data indicate for the first time a remarkable protective effect of TQ against Pb-induced testicular histopathological lesions in rat. On this basis, TQ deserves more consideration and further examination as a potential therapeutic option.